Foam phantom development for artificial vertebrae used for surgical training

Abstract

Currently the surgical training of kyphoplasty and vertebroplasty is performed on patients or specimens. To improve patient safety, a project was initiated to develop an Augmented Reality simulator for the surgical training of these interventions. Artificial vertebral segments should be integrated to provide realistic haptic feedback. To reach this, resulting forces during needle insertions (trans- and extrapedicular) into formalin-fixed vertebral specimens were measured. The same insertion procedure was also performed on six customized polyurethane blocks with varying mechanical parameters. Based on the results of these measurements, a specific foam phantom was generated and the insertion force measured. Additionally a parametric model for the needle insertion into bone was designed calculating three characteristic parameters for all insertion measurements. The resulting insertion force for the foam phantom was comparable to the specimen measurements and the parametric model provided comprehensible characteristic parameters. Based on the resulting force during needle insertion into human vertebrae, a possible foam recipe for manufacturing artificial segments was found. Furthermore, the parametric model provides characteristic parameters for the assessment of phantoms as well as the development of its production process.

Tissue mimicking materials for imaging and therapy phantoms: a review

“…In Europe, the PU foam Synbone ® TMMs are popular for surgical simulation. The density of the PU foam can be adjusted to mimic normal and osteoporotic bones (O'Neill et al 2012, Fuerst et al 2012, Hollensteiner et al 2015, Acker et al 2016 with Young's modulus of 0.02-1.1 GPa and strength of 0.6-48 MPa (Sawbones 2016). However, the Sawbones ® is still weaker than human femur in the bone drilling process (Macavelia et al 2012).…”

Investigation of a three‐dimensional printed dynamic cervical spine model for anatomy and physiology education

“…Replication of the human spine for biomechanical testing and education has been previously studied with polyurethane models (Hollensteiner et al, 2018). These models are produced through an injection molding process that does not confer the same anatomical precision that 3D printing provides, however remains a standard medium for biomechanical assessment of instrumentation and anatomical changes during iatrogenic alterations (Calvert, Trumble, Webster, & Kirkpatrick, 2010; Fuerst, Stephan, Augat, & Schrempf, 2012; Gama, Ferreira, & Barros‐Timmons, 2018). For this reason, these injection models tend to reflect a rudimentary structure of individual spinal elements, and provide a limited means for studying or teaching specific spinal pathologies or patient‐specific anatomical features, especially regarding the subtle changes of bony remodeling in degenerative conditions that affect the kinematics of the spine as a whole (Clifton, Nottmeier, Damon, Dove, Chen, & Pichelmann, 2019).…”

Ex vivo virtual and 3D printing methods for evaluating an anatomy‐based spinal instrumentation technique for the 12th thoracic vertebra

“…The hollow vertebral models were filled with polyisocyanate foam, which is less dense than the ABS filament. This provided a simulated corticocancellous interface during bone removal and instrumentation (Clifton, Damon, & Pichelmann, ; Fuerst, Stephan, Augat, & Schrempf, ; Sharp, Tanner, & Bonfield, ). The finished models were arranged according to age and sex.…”